The present invention relates to an electronic organ having means for automatically generating rhythmic patterns in the octaves of the pedals and one or more of the manuals, and in particular to such a system wherein the patterns can be manually programmed by the player.
For some time now, most electronic organs have included an easy play feature wherein various patterns of notes, such as arpeggios, are played automatically and in harmony with chords played on the accompaniment manual. By depressing either a single chord key, in the case of an organ having an automatic chord feature, or a plurality of keys to form a chord on the accompaniment manual, the organic produces a repetitive pattern of notes in the frequency range of either the accompaniment or the solo manual, and these patterns can be played either in place of or concurrently with the playing of notes on the solo manual. Many organs also include an automatic bass feature wherein an automatic bass pattern is played, again in harmony with the chord played on the accompaniment manual. In most cases, the circuitry for producing the note pattern is clocked by the rhythm unit of the organ so that the note pattern or bass pattern which is played is in time with the percussion instrument sounds, such as the drums, cymbals and other percussion instruments simulated electronically. Two examples of such note pattern generators are U.S. Pat. Nos. 4,220,068 and 4,120,225 incorporated herein by reference.
A drawback to many of the known prior art note pattern generation systems is that the patterns are hard wire programmed in a read only memory or other similar device so that the player is limited to selecting one of the patterns developed by the designers of the organ. Although this may not present a problem to the beginning player, once he progresses and becomes more familiar with the patterns, he may desire to provide his own artistic input into composing new patterns. Moreover, as tastes, and fads in music change, many of the patterns which were originally written and programmed into the organ may no longer provide much appeal with the passing of time.
Of course, read only memories can be changed, but this would involve a very expensive retrofitting of existing organs, and even in the case of newly produced organs which are based on older circuit designs, the continual reprogramming of read only memories can prove to be an expensive and time consuming operation from a manufacturing standpoint. A further dificulty lies in the rapidity with which musical tastes and fads change, so that if a new tune or melody becomes popular, there is insufficient time to reprogram the read only memories and install them in production organs before the popularity of the tune or melody has waned. Most modern day electronic organs have their circuitry concentrated into a number of large scale integrated circuit chips, which are often custom designed so that in order to recover the engineering and design costs in the chips, they must be manufactured in large quantities, thereby committing the patterns programmed by the organ designer to a certain number of production organs.
Although some prior art organs have included the capability for programming various note patterns into them, in many cases it is necessary for the player to time the programming with the rhythm unit. This presents a problem because the player must first memorize exactly which pattern he desires, and then play it in perfect synchronism with the rhythm unit so that when it is played back it will also be timed with the rhythm pattern. One prior art system which avoids the necessity for having to program the pattern in synchronism with the free-running rhythm unit is U.S. Pat. No. 4,129,055. In this system, a series of signals corresponding to either chords or single notes are programmed independently of the rhythm and then playback is effected by depressing a playback key each time the chord or note is to be changed. Although this greatly simplifies the programming step, playback is restricted because the player must successively depress the stepping key in time with the rhythm, and this leaves only one hand free to play the melody.
In other prior art automatic note pattern systems, the player may be able to program into a memory a note or bass pattern, but this will often be played back in exactly the same key in which it was patterned. For example, if the pattern is programmed in the key of D, it will be read out of the memory also in the key of D. This presents no problem as long as the pattern is programmed to fit the piece of music to be played, but if the music is transposed to a different key, of if the pattern is recalled at a different time in the musical composition which may not be in the key of D, for example, or if the pattern is recalled while playing a different piece of music, the dissonance between the read out pattern and the music being played by the performer will be quite unpleasant.
A problem which can occur where two patterns are being played simultaneously is that of phase cancellation. For example, if the note pattern produces a tone simultaneously with a tone in the bass pattern that has the same or an octavely related frequency, and if the tones are not exactly in phase, then some phase cancellation will occur. Thus, some means must be provided to protect against phase cancellation in the event that octavely related notes, that is, notes of the same frequency or at least the same pitch, are simultaneously played.